The present invention relates generally to electrical board testers, and more particularly to an algorithm for finding optimized solutions for assigning pins to probes in a constrained tester environment.
The increasing reliance upon computer systems to collect, process, and analyze data has intensified the need for reliable testing of the printed circuit boards that make up such systems. To accomplish this, industrial printed circuit board (PCB) testers are used to exhaustively test PCBs after manufacture.
Printed circuit board testers are complex machines. A typical PCB tester includes an array of tester interface pins arranged in a static configuration. The tester includes internal test hardware for configuring the connection of internal test resources to various tester interface pins. Because the locations of the tester interface pins rarely match up with the locations of the nodes of interest on a given PCB under test when the PCB under test is mounted in the tester due to the static configuration shape and pin spacing, the tester typically includes a test fixture. The test fixture includes a set of test probes that line up with the nodes of interest on the PCB under test. The probes in turn are electrically connected (for example, via a wireless (or PCB) fixture adapter) to the test interface pins when the fixture is mounted on the tester.
Prior to running a given test, the tester resources must be configured to be able to apply stimuli and receive responses appropriate to the test on various pins. One of the tasks in configuring the tester resources for a given test is to assign tester interface pins to appropriate probes of the fixture. Due to tester wiring, there are typically several constraints to satisfy in choice of pin-to-probe assignments. This type of problem is referred to herein as the “constrained pin-to-probe assignment problem”.
The following rules and constraints, referred generally hereinafter as the pin-to-probe assignment “constraints” define the constrained pin-to-probe assignment problem: